The role of time in single drop splash on thin film

This paper reports on an experimental study of the impact of water drops on thin liquid films. The morphology of the impact was studied by still photography, and quantitative results were obtained by a proper image analysis technique. The time evolution of various parameters like the crown diameter, the crown height, and the secondary drop diameters are reported, and these experimental parameters are correlated and compared to available theoretical models. A particular set-up of the acquisition system allowed us to photograph the splash from below the solid wall, allowing the first estimation of the crown thickness and the total number of jets protruding from the crown rim as a function of time. The results indicate that, for the range of the parameters investigated, there is not a strong dependence on the film thickness. The evolution of the crown height depends on the impact Weber number, whereas its growing velocity and the crown thickness evolution are almost independent of Weber number.